Designs AST node structures, implements IR-to-code transformations, applies functional programming patterns, and architects code generation backends for morphir-dotnet. Use when building or extending Morphir IR types, working with Classic/Modern IR conversions, implementing visitor patterns, or structuring code generation pipelines. Triggers include "Morphir architecture", "Morphir design patterns", "AST node", "IR transformation", "morphir-dotnet structure", "code generation backend".